1. Field of the Invention
The present invention relates to a communication system using a technique of establishing a network route. The system according to the present invention can be used for a network having a plurality of nodes connected through links and used in a telephone communication or a data communication system.
2. Description of the Related Arts
In general, a network is constituted by a plurality of nodes connected to each other through a plurality of links, communicatable terminal devices connected to the nodes, and a center station connected to the nodes through control links. The state of each of the nodes or the links is monitored by the center station, and the most suitable network route is established based on the results of the monitoring.
As one method of establishing a network route by exchanging messages between two nodes, and distributing the processings of the search for a detour route to the nodes in a network, where a failure occurs in the network, a flooding technique is used. In the flooding technique, information is transmitted simultaneously in a plurality of directions.
In the above-described system using a center station which monitors the state of each of the nodes and the links, the control signals are concentrated at the center station, and thus, in a complicated network having a large capacity, the length of time required for establishing a route is increased, which causes a problem in such a system.
In the system using the flooding technique, problems arise in that it is difficult to deal with a situation wherein a failure occurs in a node or failures occur in a plurality of links.